NTO terminals

When using the NTO licensed product, VTAM® can support some start-stop and teletype devices, known as NTO devices.

The receipt of a message can be confirmed by using transaction-response mode to lock the keyboard following the input entry. When IMS responds with available output to a particular terminal for a specific transaction, it unlocks the keyboard and sends the data.

Even if the NTO devices are used primarily for inquiry transactions, the transactions can be made recoverable. Because input is not acknowledged, the application program should indicate in the output response the inquiry transaction that caused it.

Both input and output editing routines (which are provided by your installation and are entered after MFS processing) can be made available for transactions using NTO devices.

Because NTO uses VTAM, IMS is not aware of whether a terminal user is logging on to a session or is logging off. Therefore, existing session status might cause problems when one terminal user ends a session and another terminal user resumes the session. This problem can be minimized by defining all NTO devices as Response mode.

To avoid the problem of continuing session status, a terminal user can clear any preset transaction codes that were previously set using /SET commands by entering the /RESET command either:

Before issuing the /RCLSDST command when ending an NTO session
Before issuing the /SIGN ON command when starting an NTO session

A terminal user who enters /RCLSDST or the MTO who enters /CLSDST terminates a session but does not reset conditions that were set during that session.